The present invention relates to bearings in general and more particularly to hermetically sealed prelubricated bearings.
It is desirable to seal bearings such as, for example, spherical bearing units used in the suspension or steering mechanisms of motor vehicles as passenger cars, trucks, trailers, farm tractors and implements, military vehicles, and the like, to prevent the introduction between the bearing surfaces of dirt, dust, water, and other contaminants and abrasive materials, while simultaneously preventing escape to the ambient of a lubricant, such as grease for example, prepacked in the bearing unit.
The task of effectively sealing bearings such as spherical bearings is generally accomplished by wiper seals in the form of flat metallic or plastic washers having line contact with the spherical or cylindrical peripheral surface of the bearing inner member. Wiper seals require that their wiping edge be constantly biased against the bearing inner member peripheral surface and that they be installed within the bearing unit during assembly of the diverse components of the bearing. Wiper seals are subject to rapid wear and to damage that cause their sealing capability to rapidly deteriorate, and they leave a substantial area of the bearing surfaces exposed to the ambient, with the result that when a spherical bearing is angulated an exposed and contaminated surface is brought in contact with the wiper seal edge, thus directly participating into damaging and destroying the sealing ability of the wiper seal and carrying dirt and contaminants between the bearing surfaces in engagement. Furthermore, as the wiper seals gradually deteriorate, the lubricant gradually seeps to the ambient, and the lack of insufficiency of lubrication accelerates the damaging effect.
The present invention remedies the disadvantages of the prior art by providing a hermetically sealed bearing, more particularly spherical bearing, lubricated for life, and in which the elements providing the sealing functions are separate from the element accomplishing the bearing functions, but in which, nevertheless, the functions are incorporated in an integral single unit.